According to sources speaking to Business Week, Apple's service will "scan customers' digital music libraries in iTunes and quickly mirror their collections on its own servers." Tracks not available via the iTunes Store would still need to be uploaded, but the feature would significantly reduce the amount of data that would need to be uploaded for the average user.
A side benefit of the feature is that users will be able to stream iTunes Plus versions of the songs, even if the user originally encoded the tracks as lower quality AAC or MP3 files. Such a feature was also a benefit of Lala, the streaming music service Apple bought in late 2009.
The high-bitrate streaming would be the fruit of Apple's efforts to reach licensing deals with record labels. The company is believed to have already signed deals with EMI, Warner Music, and Sony, leaving Universal as the lone holdout among the big four. There hasn't been any word on Apple attempting to reach deals with independent record labels, though it seems likely they would sign on to Apple's service once launched.
The automatic track mirroring is in sharp contrast to Amazon's Cloud Drive and Goo...